There are a couple of pieces of conventional wisdom regarding bitterness that I've begun to question. Wondering if you guys agree.
1. 'Balancing' bitterness with malt. While it's certainly true that sweet flavors tend to balance out bitter ones, I don't think that's the whole story with beer. In particular, I often find that very dry, West Coast IPAs are less bitter than I would expect, because their low FG means that they're less palate-coating than, say, an American Barleywine. I suspect that something similar might happen with high levels of carbonation, which tend to scrub the palate. Lots of bitterness up front, but less lingering bitterness.
2. Palate bitterness threshold. I don't know if anyone has a source for this, but I've heard on a number of occasions that humans have a threshold for hop bitterness, corresponding 90, 120, or whatever IBUs. I'm not sure I believe this. Has anyone tasted hop extract? How about cocktail bitters? It's certainly true that it's very difficult to make a beer over 100 IBUs, especially after packaging, and perhaps perceived bitterness does not correspond linearly with IBUs, but I have a hard time believing there's a firm ceiling within the range of bitterness that occurs in beer.